Latch mechanism



March 17, 1964 Filed Aug. 11, 1960 V. B. CETRONE ETAL LATCH MECHANISM 2 Sheets-Sheet 1 N ,l W ,go x L4 v 1 Q" A T I Sf Q l w *R @5 :e

@l w l. 5M. l m 53 w INVENTOR N N VxNcsN-r BCETRONE mi N JGERALD H.KREsr E A Tram/ff March 17, 1964 v. B. cl-:TRQNE ETAL 3,125,366

LATCH MECHANISM 2 Sheiets-Sheet 2 Filed Aug. 11, 1960 INVI'JVTORS VnNcENT BCETRONE am( G ma H. KRESKE United States Patent O 1 3,125,366 LATCH MECHANISM Vincent' Il. Cetrone, S63 Adelaide NE., Warren, Ohio,

and Gerald H. Kreslre, Warren, Ohio; said Kreslte assigner to Vincent Cetrone, Warren, Ohio Filed Aug. 11, 1960, Ser. No. 48,943 10 Claims. (Cl. 292-169) This invention relates to latch mechanisms, more particularly to such mechanisms for use with swinging doors, and the principal object of this invention is to provide new and improved mechanism of this character.

The present invention is a decided improvement over the prior art in that it reduces the number of parts required to provide an effective latch, and also minimizes the problem of corrosion because the majority, if not all, parts are formed of a rigid plastic material.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, an embodiment which this invention may assume, and in these drawings:

FIGURE 1 is a view of a latching mechanism disclosing a preferred embodiment, the cover of the housing having been removed to illustrate interior construction, and the housing being shown in position in a door, the latter being fragmentarily shown in section,

FIGURE 2 is a section corresponding to the line 2-2 of FIGURE 1, showing parts in one position,

FIGURE 3 is a section similar to FIGURE 2 but showing parts in another position,

FIGURE 4 is a section corresponding generally to the line 4 4 of FIGURE 1,

FIGURE 5 is an enlarged, fragmentary perspective view of a part of the preferred embodiment,

FIGURE 6 is a fragmentary enlarged perspective view showing details of the cover and cooperating receptacle, and

FIGURE 7 is a perspective view of a tumbler member forming part of the disclosed embodiment.

The presently preferred embodiment, as herein disclosed, comprises a housing 10 including a receptacle portion 11 and a cover 12. The housing 10 is generally oblong in plan and relatively narrow in thickness, so that it may t, in customary manner, in the usual recess 14 formed inwardly of the free margin 15 of a door 16, such as one supported in the usual manner within a door frame by means of hinges. The door frame and hinge mounting may be conventional and are therefore not shown in the drawings. The front edge wall 17 of the receptacle portion 11 (see especially FIGURE 6) is formed with tabs 18, 18, each having an aperture 19 through which a fastening screw 20 is passed to hold the housing assembled with the door in usual manner.

The front edge wall 17 is undercut, as shown at 21 in FIGURE 6 to receive the cover 12 so that the latter is iush with all upper (in FIGURE 6) edges of the receptacle portion 11. The rear edge wall of the receptacle portion (see FIGURE l) may have an arcuate outward bulge 22 for clearance of an internal Working part hereinafter to be described.

The receptacle portion 11 and cover 12 are preferably formed of a rigid plastic for purposes of economy and to obviate ordinary corrosion caused by elements which may be in the atmosphere. As an example of a plastic found suitable for the purpose, a product of the E. I. du Pont de Nemours & Company, sold under the trademark Delrin may be used. Delrin is an acetal resin, and is a high-melting, highly crystalline thermoplastic polymer. Delrin has both high tensile strength and high ilexural modulus, which qualities are combined with excellent resilience and toughness. Delrin retains these tine properties under conditions of high temperature and 3,125,366 Patented Mar. 17, 1964 ICC humidity, during an extended time under stress, or during exposure to most solvents, and it has no known equal, in a thermoplastic polymer at least, in its combination of dimensional stability, fatigue life, and recovery from deformation over a wide range of conditions.

To reduce the number of loose parts and to facilitate assembly, the cover 12 may have a plurality of tabs 23 (here four in number) extending in pairs from its opposite marginal edges, each tab terminating in a finger 24 (see FIGURE 6) adapted to snap into a respective opening 25 formed in the side edge walls of the receptacle portion 11. A slot 26 leads to the opening 25 to guide the respective finger 24 and receive the respective tab 23, and thus hold the cover in predetermined alignment with the receptacle portion.

The housing 10 provides opposed side walls, one formed by means of the bottom of the receptacle portion 11 and the other formed by the attached cover 12, and these side walls are provided with aligned openings 27, 2S, which openings are also aligned with the usual door handle apertures 29 formed in the door 16 transverse to and communicating with the door recess 14.

A tumbler member 3i) is rotatably carried within the housing 10 and has a hub 31 of a length to snugly it between the cover 12 and bottom wall of the receptacle portion 11, the hub having journals 32, 32 of reduced diameter at its opposite ends. The journals have a bearing t with the aligned openings 27, 28 to properly support the tumbler member for rotation.

The tumbler member is preferably formed of a rigid plastic, and the aforementioned Delrin has been found suitable for the purpose. A slot 33 is formed inwardly of one end of the hub 3l for a purpose to appear later. Extending from the hub are diametrically opposed pusher portions 34, 34, each terminating in a rounded extremity 35.

A latch plate 36 also preferably made of a rigid plastic, such as Delrin, is carried within the housing 10 and is preferably of a thickness to slidably t between the cover 12 and the bottom of the receptacle portion 11. The latch plate has a generally rectangular portion 37 formed with an enlarged opening 38 therein to provide operating clearance for the tumbler member 3i). The rear wall 39 of the latch plate 36 may be arcuate to clear the hub 31 and to be complementary to the rear wall 22 of the housing 1i).

The latch plate opening 38 provides a pair of strike surfaces 46 which are cooperative with the pusher member extremities 35. A latch bolt 41 is preferably integral with and extends forwardly of the rectangular latch plate portion and outwardly of the housing 10 through an opening 42 in the front edge wall 17 of the housing. The latch bolt is preferably of a width and thickness to slidably it within the opening 42 and against the cover 12 which closes such opening. An undercut neck 43 may integrally connect the latch plate portion 37 and latch bolt 41. In some instances, it is desirable to mold a hardened steel insert 44 within the latch bolt 41 to prevent easy sawing therethrough.

Resilient n eans normally projects the latch bolt in a direction outwardly of the housing 10 and such means are preferably of rigid plastic, such as Delrin. In the presently disclosed embodiment, the resilient means is integral with the latch plate 36 and comprises a pair of arcuate-shaped springs 45, either at or of other crosssection. The springs 45 in this case extend symmetrically from opposite edges of the latch plate, preferably from the neck 43. The free end of each spring 45 is headed, as shown at 46, to be slidably received within corresponding openings 47 (see FIGURE 6) formed in the front edge wall 17 of the housing 10. The latch plate 36 is Si formed symmetrical so that it may be reversed in position within the housing 10, whereby the same construction may be used for doors closing in either direction.

Suitable door handles 50, S1 extend from opposite sides of the door in the usual manner, the handles in the disclosed embodiment having door knobs S2 for hand engagement. Handle shafts 53, 54 form part of the door handles 50, 51, respectively, and the latter may be made of rigid plastic, such as the aforementioned Delrin. Each handle shaft has a circular flange 55 and each has an inner end disposed within the housing 10.

The inner end of handle shaft 53 is formed with stepped non-circular portions 56, S7 (see especially FIG- URE with the smaller portion 57 (smaller both in transverse size and length), closer to the inner terminal end of the handle shaft. The portions 56, 57 are in this case of hexagonal cross-section and cylindrical end 58, reduced in diameter extends from the smaller portion 57, the terminal face of the end 53 having a cross-slot 59 formed therein. The larger hexagonal portion 56 has a small part of its periphery rounded, as seen at 56a.

The larger hexagonal portion 56 slidably fits into a complementary portion 60 of the central opening through the tumbler member 30. The opposite end of the tumbler member opening is cylindrical, as at 61, to rotatably receive the cylindrical inner end of the handle shaft 54. The last mentioned inner end has a cylindrical axial opening 62 to rotatably receive the end 5S, this opening having a hexagonal shaped entranceway 63 to closely but slidably receive the smaller hexagonal portion 57 of the handle shaft 53. An opening 64 provides communication between the opening 62 and the exterior of the door knob 52 of the shaft 54, for a purpose to appear later.

Trim discs 65 and 66 may be used to cover the apertures 29, 29 in the door 16 in the usual manner, each trim disc being tightly held to the door by screws 67, one of which is shown in FIGURE 2. A coil spring 68 is interposed between trim disc 65 and flange 55 of handle shaft 53, to urge the latter in a direction toward the handle shaft 54 so that normally the smaller hexagonal portion 57 will seat within the entranceway 63 to couple the handle shafts for unitary rotation.

The trim discs 65, 66 may also be made of rigid plastic, such as Delrin. The spring 63 may also be made of like material and, in the case of Delrin, may be molded integrally with the disk 65. From inspection of FIGURE 2, it will be evident that the handle shaft 53 may be moved downwardly a limited amount against the urging force of the spring 68, the amount of movement being suflicient to withdraw the smaller hexagonal portion 57 from the entranceway 63 to thereby disengage the handle shafts so that only rotation of handle shaft 53 will effect operation of the tumbler member 30. Handle shaft 54, under these circumstances, may be rotated, but will not be effective to withdraw the bolt t1 from the usual keeper (not shown). The handle shaft 54 is held against axial movement, in one direction by the ange 55, and in the opposite direction by abutment of the terminal face of its inner end with the shoulder between the hexagonal and cylindrical portions 60 and 61 of the opening in the tumbler member 30.

Means are provided to releasably hold the handle shaft 53 in the retracted relation shown in FIGURE 3, and in the disclosed embodiment a lock arm '70 is integrally formed with the cover 12 and has a finger 71 (shown in phantom in FIGURE 1) which extends through the slot 33 in the hub 31 of the tumbler member 30, and bears against the rounded peripheral surface 56a. The finger is resiliently pressed in a direction toward the axis of the handle shaft 53 and is adapted, when the shaft 53 is retracted, to snap into a recess 72 (see FIGURE 5) formed in the end of the larger hexagonal portion. The recess 72 provides a shoulder 73 which engages the nger and thus holds the shafts retracted.

Sufiicient rotation of the shaft 53 (slightly less than 90 degrees in the present case) will rotate the recess beyond the finger and, since no shoulder is then in line with the finger, the spring 68 will return shaft 53 to position wherein its inner end interfits with the inner end of the shaft 54 in driving relation. The latch thus described may be used as a bathroom lock, with the shaft 53 innermost of the room. In order that children cannot lock themselves in the bathroom without means of escape provided from the outside, a long, narrow screwdriver blade, or like tool, may be inserted into the opening 64- to seat in the slot 5@ and thus provide means to rotate the shaft 53 from the outside of the room.

The latch parts are rfew and may be easily assembled. With the cover 12 removed, the latch plate 36 may be quickly and easily disposed within the housing y10 merely by inserting the headed ends 46 of the springs 45 into the corresponding openings 47 in the receptacle portion 11. The tumbler member 30 may then be disposed in position within the opening 3S in the latch plate 36 and with one journal 32 in the opening 23 in the receptacle portion. The cover 12 may then be snapped into place, the arm 70 having been manipulated to dispose the finger 71 into the slot 33 in the tumbler member 3f). Thereafter, the handle shafts 53 and 54 are respectively inserted from the outer `and inner sides of the door 16 and the screws 67 driven home. The latch is then ready for use. Since the parts, with the possible exception of the screws 20 and 67, are all formed of rigid plastic, the corrosion problem is largely overcome, and the latch may be used in places where rusting had heretofore made the life of a latch a short one.

In view of the foregoing, it will be apparent to those skilled in the art that we have accomplished at least the principal object of our invention, and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed em-bodiment is illustrative only, and that our invention is not limited thereto.

We claim:

l. A latch mechanism for a door, comprising a relatively flat housing including spaced side walls having aligned openings, said housing being adapted to bc inserted edgewise into a recess in a margin of the door and aligned with door handle apertures in the door, a relatively flat latch plate disposed flatwise within said housing and having opposite edge margins slidably engaging with opposed inner surfaces of said housing to mide said latch plate for reciprocating movement within said housing, said latch plate having a latch bolt extending through an opening in an edge wall of said housing and projectable to latching cooperation with a keeper carried by the door jarnb, said latch plate having an enlarged opening therethrough providing strike surfaces on opposite sides of the center of the aligned side wall openings, a tumbler member having journals rotatably mounted in said side wall openings and having pusher portions respectively engage-able with said strike surfaces whereby rotation of said tumbler member in opposite directions effects reciprocation of said latch plate, a pair of springs of arcuate shape disposed on opposite edges 0f said latch plate and extending between such edges and said housing to resiliently project said latch bolt outwardly of said housing, a pair of handle shafts extending from opposite sides of said housing and adapted to extend from opposite sides of said door, said Ihandle shafts having inner ends within said housing, one of said inner ends having stepped noncircular portions with the smaller portion closer to its inner terminal, the larger portion slidably iitting within a corresponding hole in said tumbler member so that said one inner end may be moved in a direction outwardly of said housing a limited amount without affecting rotating relation lbetween said One inner end and said tumbler member, the other inner end having a corresponding non-circular socket slidably receiving the smaller stepped nonJcircular portion of said one inner end so that said other inner end may also rotate said tumbler member but said smaller portion may be withdrawn from its socket to interrupt driving relation therebetween.

2. The construction according to claim 1 wherein all of the parts mentioned therein are formed of rigid plastic material.

3. The construction according to claim 1 wherein said latch plate and said springs are integral.

4. The construction according to claim 1 and further including a peripheral recess in the larger stepped portion and a spring finger on said housing to engage in said recess and hold said inner end in position wherein said smaller stepped portion is withdrawn from its socket.

5. The construction of claim 4 and further including an axial opening in said other inner end to pass a screwdriver blade, the extremity of said blade being adapted to seat in a slot in the inner terminal of said one inner end for the purpose of rotating the latter.

6. A latch mechanism, comprising a housing, a latch plate mounted within said housing for reciproeation and including a latch bolt projectable from said housing for latching cooperation with a keeper, and resilient means for rurging said latch plate in a direction wherein said latch bolt is projected from said housing, said latch plate and said resilient means -being integrally formed of a high-melting thermoplastic polymer.

7. The construction according to claim 6 wherein said housing is also formed of a high-melting thermoplastic polymer.

8. The construction according to claim 6 wherein said resilient means comprises a pair of iiat springs of arcuate shape and symmetrically disposed on opposite side edges of said latch plate and tixed in position between said edges and said housing.

9. The construction according to claim 8 wherein each of said flat springs has a headed extremity received within a complementary recess formed in said housing, whereby one end of each spring is fixed to said latch plate by its integral connection and the other end of each spring is ixed to said housing by seating its headed extremity within its respective complementary recess, the intermediate portion ot each spring being bowed to provide the desired spring action,

10. A latch mechanism for a door, comprising a relatively at housing including spaced side walls having aligned openings, said housing being adapted to be inserted edigewise into a recess in a margin of the door with its openings aligned with door handle openings in said door, a relatively flat latch plate disposed ilatwise within said housing, said latch plate having opposite edge margins slidably and smoothly engaging Iwith opposed inner surfaces of said housing to guide said latch plate for reciprocating movement within said housing, said latch plate having a ylatch bolt extending through an opening in an edge wall of said housing and projectable to latching cooperation with a keeper carried by the jamb of the door way closed by said door, said latch plate having an enlarged opening therethrough providing strike surfaces on Iopposite sides of the center of the aligned wall openings, a tumbler member having journals rotatably mounted in said side wall openings and having pusher portions respectively engageable with said strike surfaces whereby rotation of said tubuler member in opposite directions effects reciprocation of said latch plate, a pair of dat springs of arcuate shape and symmetrically disposed on opposite sides of said latch bolt and iixed between said sides and said housing to resiliently project said latch bolt outwardly tof said housing, said latch plate, said latch bolt and said ilat springs being integrally formed of a high-melting thermoplastic polymer, and handle sharft means connected to said tumbler member and adapted to be manually rotated to eiect rotation of said tumbler member.

References Cited in the iile of this patent UNITED STATES PATENTS 182,240 Steele Sept. l2, 187.6 550,424 Smith Nov. 26, 1895 697,599 Barrett Apr. 15, 1902 782,115 Dyer Feb. 7, 1905 1,880,675 Baume Oct. 4, 1932 2,246,086 Austin June 17, 1941 2,271,966 Baribault Feb. 3, 1942 2,315,102 Adams Mar. 30, 1943 2,375,357 Friedman May 8, 1945 2,469,113 Hooker M-ay 3, 1949 2,497,329 Smith et al. Feb. 14, 1950 

6. A LATCH MECHANISM, COMPRISING A HOUSING, A LATCH PLATE MOUNTED WITHIN SAID HOUSING FOR RECIPROCATION AND INCLUDING A LATCH BOLT PROJECTABLE FROM SAID HOUSING FOR LATCHING COOPERATION WITH A KEEPER, AND RESILIENT MEANS FOR URGING SAID LATCH PLATE IN A DIRECTION WHEREIN SAID LATCH BOLT IS PROJECTED FROM SAID HOUSING, SAID LATCH PLATE AND SAID RESILIENT MEANS BEING INTEGRALLY FORMED OF A HIGH-MELTING THERMOPLASTIC POLYMER. 